Note: Descriptions are shown in the official language in which they were submitted.
CA 02781985 2012-06-29
SELF-POWERED LOCK SYSTEM WITH PASSIVE ID DETECTION
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The present application claims priority on U.S.
Application No. 61/503041, filed on June 30, 2011.
TECHNICAL FIELD
[0002] The present invention relates to the field of
electronic lock systems, and particularly to self-powered
electronic lock systems.
BACKGROUND
[0003] Electronic or electric lock systems include locking
devices that operate by means of an electrical current. Some
electronic lock systems are powered by an external electrical
energy source. For example, an electronic lock system can be
line-powered, i.e. powered from a standard electrical utility
system. In another example, an electronic lock system can be
battery-powered.
[0004] Other electronic lock systems are self-powered and
comprise an electrical energy generator which is driven by a
door handle or lever used by a user for opening the door to
which the self-powered lock system is secured.
[0005] Some electronic lock systems comprise an
authentication device for authenticating and granting access
to a user. For electronic lock systems powered by an external
power source, the user first enters his identification (ID)
using the authentication device. If the ID is valid, the lock
mechanism is unlocked and the user is free to open the door.
For self-powered electronic lock systems, the user has first
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to manually activate the door handle connected to the
generator for powering the lock system. When sufficient
energy has been generated, the electronic lock provides the
user with a visual or audible signal for indicating that it
is ready to be used. The user then authenticates himself
using the authentication system and the lock mechanism is
unlocked. Having to activate the door handle before
authentication is not intuitive since externally powered
electronic lock systems do not require any action from the
user before authentication. Therefore, users of a self-
powered electronic lock have to be instructed on the method
of using the self-powered electronic lock system, which is
time-consuming in addition of being inconvenient.
[0006] Therefore, there is a need for an improved self-
powered electronic lock system.
SUMMARY
[0007] According to a first broad aspect, there is
provided a self-powered lock system for a movable member, the
system comprising an energy storage device having an
electrical charge stored therein; a generator coupled to the
storage device and adapted to generate electrical energy; a
lock mechanism having a first state in which the movable
member is locked and a second state in which the movable
member is unlocked; a control unit coupled to the lock
mechanism and adapted to place the lock mechanism in one of
the first state and the second state; a trigger unit adapted
to be activated with the lock mechanism in the first state,
an activation of the trigger unit triggering a placement of
the lock mechanism in the second state; and a passive
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detection unit coupled to the trigger unit and to the control
unit, the detection unit detecting the activation of the
trigger unit and, upon detection of the activation, providing
a conductive path between the control unit and the storage
device, thereby powering the control unit with the stored
electrical charge, the control unit, upon being powered,
placing the lock mechanism in the second state and triggering
a storage of the generated electrical energy in the storage
device for future use.
[0008] According to a second broad aspect, there is
provided a control system for controlling a self-powered
electronic lock for a movable member, the lock comprising an
electrical energy generator and a lock mechanism having a
first state in which the movable member is locked and a
second state in which the movable member is unlocked, the
control system comprising an energy storage device having an
electrical charge stored therein; a control unit coupled to
the lock mechanism and adapted to place the lock mechanism in
one of the first state and the second state; a trigger unit
adapted to be activated with the lock mechanism in the first
state, an activation of the trigger unit triggering a
placement of the lock mechanism in the second state; and a
passive detection unit coupled to the trigger unit and to the
control unit, the detection unit detecting the activation of
the trigger unit and, upon detection of the activation,
providing a conductive path between the control unit and the
storage device, thereby powering the control unit with the
stored electrical charge, the control unit, upon being
powered, placing the lock mechanism in the second state and
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triggering a storage of the generated electrical energy in
the storage device for future use.
[0009] In accordance with a further broad aspect, there is
provided a method for controlling an electronic lock of a
movable member, the method comprising passively detecting an
activation of a trigger unit with the lock in a locked state;
upon said detection, providing a conductive path between a
control unit coupled to the lock and a storage device having
an electrical charge stored therein, thereby powering the
control unit with the stored electrical charge; upon said
powering, the control unit placing the lock in an unlocked
state; and charging the storage device for a next use with
electrical energy generated by a generator coupled to the
storage device.
[0010] The present self-powered electronic lock system may
be operated as a battery-powered electronic lock system. In
one embodiment, the generator is an electric generator
operatively connected to a door lever to convert at least
some of the mechanical energy generated during a manual
operation of the door lever to electrical energy. Each time
the generator is driven by the manual operation of a door
lever during use of the lock system, the electrical energy
generated by the generator is stored for a next use. Since
the electrical energy is generated and accumulated during a
normal operation of the lock system, the lock system may be
seen as having "energy harvesting" capabilities. As a result,
the user uses the present self-powered electronic lock system
as he would use a battery-powered electronic lock system,
i.e. the user first enters a user ID and then opens the door
by operating the door lever, for example.
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BRIEF DESCRIPTION OF THE DRAWINGS
[0011] Further features and advantages of the present
invention will become apparent from the following detailed
description, taken in combination with the appended drawings,
in which:
[0012] Fig. 1 is a block diagram of a self-powered
electronic lock system, in accordance with a first
embodiment;
[0013] Fig. 2 is a flow chart illustrating a method for
operating a self-powered electronic lock system, in
accordance with an embodiment;
[0014] Fig. 3 is a block diagram of a self-powered
electronic lock system, in accordance with another
embodiment; and
[0015] Fig. 4 illustrates a self-powered electronic lock
system comprising electronic circuitry, in accordance with an
embodiment.
[0016] It will be noted that throughout the appended
drawings, like features are identified by like reference
numerals.
DETAILED DESCRIPTION
[0017] Figure 1 illustrates one embodiment of a self-
powered electronic lock system 10 comprising a lock mechanism
12 of which the unlocking is triggered by a trigger unit 14.
The lock system 10 further comprises a generator 16 to be
manually operated for generating electrical energy, an
electrical energy storage unit 18 for storing the electrical
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energy generated by the generator 16, a control unit 20 for
controlling the operation of the lock system 10, a passive
detection unit 22 adapted to detect the activation of the
trigger unit 14 while consuming no electrical energy, and a
switch 24.
[0018] The generator 16 is operatively connected to a door
handle or lever (not shown) of which a displacement drives
the generator 16. The door handle may be any adequate
mechanical device that can be used for opening a door and
operatively connected to the generator 16 so as to drive the
generator 16 upon operation by a user, i.e. when the user
displaces the mechanical device. Examples of adequate door
handles comprise a knob, a lever, a panic bar, and the like.
The generator 16 is electrically connected to the electrical
energy storage unit 18 so that electrical energy generated by
the generator 16 upon operation of the door handle by a user
is stored therein. The switch 24 electrically connects the
electrical energy storage unit 18 and the control unit 20 and
controls the powering of the control unit 20 from the
electrical energy storage unit 18. The control unit 20 is
configured for powering the lock mechanism 12 in order to
unlock the lock mechanism 12.
[0019] In one embodiment, the self-powered electronic lock
system 10 further comprises an authentication unit 26
connected to the control unit 20. Once the trigger unit 14
has been activated by the user and the control unit 20 has
been powered, the authentication unit 26 is powered by the
control unit 20. The authentication unit 26 is used by the
user to enter an identification which is transmitted to the
control unit 20. The control unit 20 then compares the
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received user ID to a list of authorized IDs. If the user ID
is valid, then the control unit 20 powers and unlocks the
lock mechanism 12. It should be understood that any adequate
authentication unit 26 may be used. For example, the
authentication unit 26 can be a keypad for entering a
numerical code, password, and/or passphrase, a biometric
sensor, a radio-frequency identification (RFID) reader for
reading an RFID tag, or the like.
[0020] While the closing of the switch 24 is controlled by
the passive detection unit 22, different scenarios for the
subsequent opening of the switch 24 may be possible. In one
example, the switch 24 is adapted to close for powering the
control unit 20 for a predetermined period of time. In
another example, the opening of the switch 24 is controlled
by the control unit 20. In this case, the control unit 20 may
be adapted to send a control signal to the switch 24 as long
as it requires to be powered and the switch 24 opens as soon
as no control signal is received from the control unit 20. In
a further example, the switch 24 remains closed for powering
the control unit 20 as long as no stop signal is received
from the control unit 20.
[0021] In one embodiment, the control unit 20 is
configured for unlocking the lock mechanism 12 for a
predetermined period of time such as 2s, 5s, or the like. It
should be understood that the predetermined period of time is
chosen as a function of the storage capacity of the energy
storage unit 18 and the electrical consumption of the system
10. Once the predetermined period of time has elapsed, the
control unit 20 stops powering the lock mechanism 12 which
locks. Alternatively, the control unit 20 may send a lock
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signal to the lock mechanism 12 in order to lock the lock
mechanism 12 while still powering the lock mechanism 12.
[0022] The generator 16 may be any adequate device that
generates electrical energy using a source of energy other
than electrical energy. For example, the generator 16 may be
an electric generator that converts mechanical energy
generated by the activation of the door handle to electrical
energy, as described above. For example, the generator 16 may
be an electrical motor, a step motor, or the like. While in
the description it is operatively connected to a door handle,
it should be understood that the electric generator may be
operatively connected to the door so that electrical energy
be generated while a user opens the door. The generator 16
may also generate electrical energy from energy sources other
than mechanical energy source, such as thermal or solar
energy source. For example, the generator may be solar cell
or a combination of solar cells installed on the door for
example.
[0023] The electrical energy storage unit 18 may be any
adequate device adapted to store electrical energy. Examples
of adequate electrical energy storage unit comprise
rechargeable batteries, capacitors such as aluminum
electrolytic capacitors or solid-state capacitors for
example, supercapacitors, and the like.
[0024] The lock mechanism 12 may be any adequate door
fastener of which the locking and unlocking may be
electrically controlled. For example, the lock mechanism 12
may be a magnetic lock, an electric lock or electric latch
release, or the like. The lock mechanism 12 may also be a
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mechanical piece operatively connected to a door latch and
movable between a first position in which the latch is
allowed to move, thereby allowing a user to open the door,
and a second position in which the latch is prevented from
moving, thereby preventing the user from opening the door.
[0025] It should be understood that the lock system 10 may
be used for controlling the lock/unlock state of any movable
structure used to close off an entrance. For example, the
lock system 10 may be used for controlling an entrance door,
a safety door, a safe door, or the like.
[0026] Figure 2 illustrates one embodiment of a method 50
for operating the electric lock system 10. The first step 52
comprises passively detecting a manual activation of the
trigger unit 14 via the passive detection unit 22. It should
be understood that this step requires substantially no
electrical energy consumption since the passive detection
unit 22 consumes substantially no electrical energy for
detecting the manual activation of the trigger unit 14. Upon
detection of the activation of the trigger unit at step 52,
the passive detection unit 22 is powered using the energy
stored in the energy storage unit 18 and triggers the closing
of the switch 24, and therefore the powering of the control
unit 20 by the energy storage unit 18 via the switch 24, at
step 54. Similarly, the triggering of the closing of the
switch 24 by the passive detection unit 22 requires
substantially no electrical energy consumption since the
passive detection unit 22 consumes substantially no
electrical energy until the closing of the switch 24.
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[0027] At step 56, the control unit 20 triggers the
unlocking of the lock mechanism 12 by powering the lock unit
12 using the energy received from the energy storage unit 18.
A visual and/or audible signal indicative of the unlock
status for the lock mechanism 12 may be provided to the user
for indicating that the lock device is unlocked. At step 58,
the user charges the energy storage unit 18 by opening the
door. Since the door handle is operatively connected to the
generator 16, the operation of the door handle drives the
generator 16 which generates electrical energy. The
electrical energy generated by the generator 16 is then
stored in the energy storage unit 18 for a future opening of
the door.
[0028] It should be understood that the energy storage
unit 18 is charged before the first use of the self-powered
electronic lock system 10. Then, each operation of the handle
for opening of the door charges the energy storage unit 18
for a subsequent use of the lock system 10.
[0029] The passive detection unit 22 may be any adequate
unit adapted to detect a manual activation of the trigger
unit 14 while consuming substantially no electrical energy,
and trigger the closing of the switch 24. Figure 3
illustrates one embodiment of a self-powered electronic lock
system 60 comprising a trigger switch 64 for triggering the
unlocking of a lock mechanism 62. The lock system 60 further
comprises a generator 66 operatively connected to a door
handle (not shown) to be manually operated for generating
electrical energy, a capacitor 68 for storing the electrical
energy generated by the generator 66, a control unit 70 for
controlling the operation of the lock system 60, a potential
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variation detector 72 adapted to detect the activation of the
trigger switch 64 while consuming substantially no electrical
energy and trigger the powering of the control unit 70, and a
switch 74 connected between the capacitor 68 and the control
unit 70. The capacitor 68 has one terminal 68a connected to
the potential variation detector 72 and the switch 74 while
the other terminal 68b is grounded.
[0030] The trigger switch 64 comprises first and second
electrical contacts 76 and 78. The trigger switch 64 further
comprises a mechanical movable connector (not shown) to be
manually operated for electrically connecting the two
contacts 76 and 78 together. In one example, one of the two
contacts 76 and 78 may be movable between an open position in
which the movable contact is away from the other contact and
a closed position in which the movable contact is
electrically connected to the other contact. In this case,
the mechanical connector may be a push button to be manually
operated by a user for moving the movable contact in the
closed position. In another example, the two contacts 76 and
78 may have a fixed relative position and the mechanical
connector may be a push button provided with an electrical
conductor element for electrically connecting the two
contacts 76 and 78 upon depression of the push button by the
user. It should be understood the mechanical connector may be
any adequate mechanical device which allows the two contacts
76 and 78 to be electrically connected together upon manual
operation thereof. While the description refers to a push
button, other examples of adequate mechanical connectors
comprise a switch, a lever, and the like.
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[0031] In the open position, the two contacts 76 and 78
are each maintained at a different electrical potential. The
contact 76 is connected to the terminal 68a of the capacitor
68 via the potential variation detector 72 so that the
contact 76 be maintained at a first non-zero electrical
potential while the contact 78 is maintained at a second
electrical potential different from the first electrical
potential. For example, the contact 78 may be grounded.
[0032] Upon manual operation of the trigger switch 64 by
the user in order to trigger the unlocking of the lock
mechanism 62, the two contacts 76 and 78 are electrically
connected together and the electrical potential of the
contact 76 varies. The potential variation detector 72
detects the variation of electrical potential for the contact
76 while consuming substantially no electrical energy. The
variation of electrical potential triggers the powering of
the potential variation detector 72 from the capacitor 68.
Once powered, the potential variation detector 72 closes the
switch 74 to power the control unit 70 using the energy
stored in the capacitor 68. Then the control unit 70 powers
the lock mechanism 62 which unlocks for a predetermined
period of time before locking again. In one embodiment, the
control unit 70 powers the lock mechanism 62 during the whole
predetermined period of time. Alternatively, the control unit
powers the lock mechanism 62 for unlocking the lock, then
stops powering the lock mechanism 62, and then powers again
the lock mechanism 62 for locking the lock mechanism 62 after
the predetermined period of time.
[0033] In one embodiment, the lock system 60 may further
comprise an authentication unit powered by the control unit
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70. In this case, the authentication is adapted to allow a
user to enter his user ID. The user ID is then sent to the
control unit 70 which verifies whether the user ID is valid
before unlocking the lock mechanism 62. In one embodiment,
the authentication unit is integral with the trigger switch
64. One example of an adequate integrated authentication unit
and trigger switch may be a keypad which is used by the user
to enter a numerical code, password, and/or passphrase.
[0034] Figure 4 illustrates one embodiment of a self-
powered electronic lock system 100 comprising a keypad 102
for both triggering the powering of the lock system in order
to unlock a lock mechanism 104 and entering a user ID. The
lock system 100 is adapted to detect a key activation on the
keypad 102 without any active power consumption. As a result,
the lock system 100 operates as a battery powered lock system
since the user can simply first enter his user ID before
operating the door handle for opening the door.
[0035] The lock system 100 further comprises a generator
106 for generating electrical energy, a microcontroller 108
for controlling the operation of the lock system 100, a
capacitor 110 for storing electrical energy, and an
electronic circuit 112 which interconnects the keypad 102,
the lock mechanism 104, the generator 106, the capacitor 110,
and the microcontroller 108 together. The generator 106 is
operatively connected to the handle of the door which is
provided with the lock mechanism 104, for example. The manual
operation of the door handle by a user drives the generator
106 which generates electrical energy. The generated
electrical energy is then stored in the capacitor 110.
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[0036] As illustrated in Figure 4, the generator 106 is
connected to the capacitor via two bridge rectifiers 114 and
116 which convert the Alternating Current (AC) electrical
current generated by the generator 106 into an adequate
Direct Current (DC) electrical current for charging the
capacitor 110. It should be understood that the capacitor 110
is chosen to store therein enough energy for powering the
lock system 100 during at least one use thereof. Similarly,
the generator 106 is chosen to generate enough electrical
energy for charging the capacitor 110 during a single manual
operation of the door handle.
[0037] The keypad 102 comprises a plurality of buttons or
keys organized as rows and columns to form a matrix. In the
present embodiment, the keypad buttons are organized
according to a matrix comprising three columns and four rows.
Each button column is associated with a respective column
electrical connection 118a, 118b, 118c which is connected to
the microcontroller 108. For example, the buttons of the
first column, i.e. the "1", "4", "7", and "*" buttons, are
each associated with the column electrical connection 118a.
Each button row is associated with a respective row
electrical connection 120a, 120b, 120c, 120d which is also
connected to the microcontroller 108. For example, the
buttons of the second row, the "4", "5", and "6" buttons, are
each associated with the row electrical connection 120b. When
the keypad is not used, the row and column electrical
connections 118-118c and 120a-120d are not electrically
connected together. By depressing a given keypad button, its
respective row and column electrical connections electrically
connect together. For example, by depressing the button "8"
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of the keypad, the row electrical connection 120c and the
column electrical connection 118b electrically connect
together.
[0038] A capacitor 122a, 122b, 122c, and 122d is present
along a respective row electrical connection 120a, 120b,
120c, and 120d between the keypad 102 and the microcontroller
108. Each capacitor 122a, 122b, 122c, and 122d acts a filter
which allows varying or AC electrical signals to propagate
from the keypad 102 to the microcontroller 108 while
preventing steady-state or DC electrical signals from
propagating from the keypad 102 to the microcontroller 108.
Each row electrical connection 120a, 120b, 120c, and 120d are
electrically connected to the positive terminal of the
capacitor 110 via a respective resistor 124a, 124b, 124c, and
124d, and a transistor 126. As a result, when the capacitor
110 is charged, each row electrical connection 120a, 120b,
120c, and 120d is maintained at a non-zero electrical
potential. The capacitors 122a, 122b, 122c, and 122d act as
an isolator between the microcontroller 108 and the row
electrical connections 120a, 120b, 120c, and 120d, thereby
allowing the electrical potential of the row electrical
connections 120a, 120b, 120c, and 120d to be maintained. As a
result, the voltage applied to the row electrical connections
120a, 120b, 120c, and 120d when the lock system 100 is not in
use does not flow through the microcontroller 110 and
substantially no electrical energy is consumed. Similarly,
each column electrical potential 118a, 118b, and 118c is
maintained an electrical potential which is different from
that of the row electrical connection 120a, 120b, 120c, and
120d. For example, the column electrical potential 118a,
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118b, and 118c may be grounded via resistors 152a, 152b, and
152c, respectively.
[0039] The transistor 126 is further electrically
connected to a first voltage detector 128 via two transistors
130 and 132 such as bipolar junction transistors or metal-
oxide-semiconductor field-effect transistors (MOSFETs) for
example. The first voltage detector 128 is electrically
connected to a regulator 134 via a diode 36 and two
transistors 138 and 140. The regulator 134 is further
electrically connected to the capacitor 10 via the transistor
140 and to the microcontroller 108 and is used for powering
the microcontroller 108 using the electrical energy stored in
the capacitor 110. In addition, the microcontroller 108 is
connected to a driver 142 connected to the lock mechanism
104.
[0040] The lock system 100 operates as follows. It should
be understood that the capacitor 110 has to be charged before
the first use of the system 100. The door handle operatively
connected to the generator 106 may be operated to drive the
generator 106 and charge the capacitor 110 before the first
use of the lock system 100.
[0041] Once the capacitor 110 has been charged, the self-
powered lock system 100 can be used as a battery powered lock
system, i.e. the user first enters his ID using the keypad
102 and then manually operates the handle to open the door.
[0042] In order to unlock the lock mechanism 104, a user
first enters his ID using the keypad 102. The user starts by
depressing the button corresponding to the first ID element,
such as the "3" button for example. The depression of the
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button electrically connects its respective row and column
electrical connections together. Since the respective row and
column electrical connections are maintained at different
electrical potentials before the depression of the keypad
button, electrically connecting the respective row and column
electrical connections together changes the electrical
potential of the respective row electrical connection. For
example, the depression of the "3" button interconnects the
row electrical connection 120a and the column electrical
connection 118c together, and the electrical potential of the
row electrical connection 120a varies. In the present
embodiment, the electrical potential for the row electrical
connection 120a decreases down to a low level, such as close
to zero for example, since the column electrical connection
118c is grounded via resistor 152c. The transistor 126 which
acts as a passive potential detector detects the variation of
electrical potential for the respective row electrical
connection, such as electrical connection 120a for example,
while consuming no electrical energy. The variation of
electrical potential triggers the powering of the electric
circuit 112. The variation of electrical potential for the
respective row electrical connection activates the transistor
126 so that it conducts and activates in turn the transistor
130. When the transistor 130 conducts, the transistor 132 is
activated which allows electrical energy stored in the
capacitor 110 to reach the voltage detector 128. If the
voltage applied to the detector 128 is above a predetermined
threshold, the voltage detector 128 outputs a logic high
which activates the transistor 138 via the diode 136, which
in turn activates the transistor 140. When the transistor 140
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conducts, the regulator 134 is powered by the capacitor 110,
which in turn powers the microcontroller 108.
[0043] When powered, the microcontroller 108 first
receives the user ID from the keypad, then determines the
validity of the user ID, and finally unlocks the lock
mechanism 104 if the user ID is valid. The reception of the
user ID by the microcontroller 108 from the keypad 102 occurs
as follows. Once powered, the microcontroller 108 sends an
electrical pulse on each column electrical connection 118a,
118b, and 118c towards the keypad 102. When a particular
button is depressed, its corresponding row and column
electrical connections electrically interconnects and the
electrical pulse propagating on the corresponding column
electrical connection can reach the corresponding row
electrical connection. Then, the electrical pulse propagates
on the corresponding row electrical connection up to the
microcontroller 108 via the capacitor 122a-122d present along
the corresponding electrical row connection since the
electrical pulse is a varying signal and can therefore be
transmitted by the corresponding capacitor 122a-122d. Knowing
from which row electrical connection the pulse signal is
received, the microcontroller 108 can determine which keypad
button is depressed. Following the detection of the
depression of a second keypad button, the microcontroller 108
sends another pulse signal on each column electrical
connection 118a, 118b, and 118c in order to determine the
second ID code element entered by the user, i.e. to identify
the second keypad button that is being depressed by the user.
[0044] Referring back to the example in which the first ID
element entered by the user is a "3", i.e. when the user
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first depresses the "3" button, the electrical connections
118c and 120a electrically connect together so that the
electrical pulse propagating on the column electrical
connection 118c reaches the row electrical connection 120a
before propagating up to the microcontroller 108 via the
capacitor 122a. Upon reception of the signal from the row
electrical connection 120a, the microcontroller 108
determines that the "3" button is depressed. Then, after the
detection of the depression of a second keypad button, the
microcontroller 108 sends a second electrical pulse on each
one of the column electrical connections 118a, 118b, and 118
to identify the second depressed keypad button.
[0045] It should be understood that the time required for
detecting that a button has been depressed, powering the
microcontroller 108 and determining which button has been
depressed is shorter or substantially equal to the time
during which the button is depressed.
[0046] Once the microcontroller 108 has determined all of
the ID elements, the validity of the user ID is verified. If
the user ID is valid, the driver 142 is powered by the
microcontroller 108. When powered, the driver 142 unlocks the
lock mechanism 104 and a visual and/or audible signal (not
shown) may be provided to the user for indicating that the
lock mechanism 104 is unlocked. The user then operates the
door handle for opening the door and the manual operation of
the handle drives the generator 106. The electrical energy
generated by the generator 106 is stored in the capacitor 110
for a next use of the lock system 100, i.e. the next
unlocking of the lock mechanism 104.
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[0047] As a result, the lock system 100 is capable of
harvesting electrical energy generated from a normal
operation in order to power the elements of the lock system
100. The energy stored during a particular operation is
stored for a subsequent use of the lock system 100 and all of
the elements of the lock system 100 are disconnected at the
end of the particular operation, so that the lock system 100
consumes substantially no electrical energy between uses. The
elements of the lock system 100 are then reconnected when the
user depresses a key on the keypad 102 and the electrical
energy previously generated and stored in the capacitor 110
is used for powering the lock system for the new operation
cycle. Therefore, the lock system 100 may be used without
having to activate the door handle before entering the user
ID.
[0048] The electrical circuit 112 further comprises a
diode 144 for electrically connecting the microcontroller 108
to the transistor 138. The microcontroller 108 can then force
the regulator 134 to provide power thereto by applying an
electrical signal, such as a high signal, to the transistor
138 via the diode 144 to activate the transistor 138 as long
as the microcontroller 108 requires to be powered.
[0049] In one embodiment, the circuit 112 further
comprises a diode 146 which connects the generator 106 to the
transistor 130 in order to provide the microcontroller 108
with power during the operation of the generator 106. As a
result, the operation of the door handle which drives the
generator 106 causes the microcontroller 108 to be powered.
Upon manual operation of the handle, the generator 106
applies an electrical signal to the transistor 130 through
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the diode 146 which converts the AC current generated by the
generator 106 to a DC current. As described above, if the
voltage detector 128 determines that the voltage of the
capacitor 110 is greater than a predetermined threshold, then
the transistors 138 and 140 are activated to provide the
microcontroller 108 with power via the regulator 134.
[0050] In the same or another embodiment, the circuit 112
further comprises a diode 148 and a transistor 150 which
connect the generator 106 to the microcontroller 108 for
informing the microcontroller 108 that the generator 106 is
in operation, assuming the microcontroller 108 is powered.
Upon manual operation of the door handle, the generator 106
applies an electrical signal to the transistor 150 through
the diode 148 which converts the AC current generated by the
generator 106 to a DC current. When the transistor 150
conducts, an electrical signal, such as a pulsed signal for
example, is applied to the microcontroller 108 which, if
powered, determines that the generator operates.
[0051] While in the present description, the keypad
buttons are organized as rows and columns, it should be
understood that other configurations are possible. For
example, the keypad buttons may be organized as a single row
or column so that each button is associated with a respective
column electrical connection 118 and a respective row
electrical connection 120, and that each column electrical
connection and each row electrical connection is associated
with a single keypad button.
[0052] While the variation of the electrical potential of
the row electrical connections 120a-120d is used for
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triggering the powering of the microcontroller 108, it should
be understood that the electrical potential of the column
electrical connections 118a-118c may be used for triggering
the powering of the microcontroller 108. In this case, the
column electrical connections 118a-118c are electrically
connected to the transistor 126 so that their electrical
potential be maintained to a first electrical potential and
to the microcontroller 108 through the capacitors 122a-122d.
The row electrical connections 120a-120d are then directly
connected to the microcontroller 108 in addition to being
grounded via the resistors 152a, 152b, and 152c.
[0053] The energy harvested during a door handle operation
is at least equal to the energy used by the microprocessor
108 and the electronic circuit 112 during an opening cycle.
Therefore, during a normal operation cycle where access is
granted and the user operates the door handle, the energy
stored in the storage capacitor 110 is sufficient for the
next operation cycle. When the microcontroller 108 sends a
stop signal, such as a low signal for example, to the
transistor 138 through the diode 144 at the end of an opening
cycle, the power provided to the electronics is turned off.
The charge on the storage capacitor 110 is then conserved
until the next opening cycle. As a result, the user can
simply enter the code without prior operation of the door
handle.
[0054] In one embodiment, if the user ID entered by the
user is valid and access is granted, the microcontroller 108
sends a signal to the driver 142 for unlocking the lock
mechanism 104. The user then operates the door handle to open
the door and thus recharges the capacitor 100. After a
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predetermined period of time, the microcontroller 110 sends a
second signal to the driver 142 to lock the lock mechanism
104 before sending a low signal to the transistor 138 through
the diode 144 for turning off the power.
[0055] As described above, the electronic circuitry is
completely disconnected between uses. When the lock system is
not in use, the power consumption is only caused by the
leakage of the semiconductor devices and capacitors. In one
embodiment, a leakage current of about 50 pA or less may be
achieved by adequately selecting the electric and electronic
components. In comparison, the use of powered semiconductors
such as low-power microcontrollers between lock uses would
increase the power consumption by about three or four orders
of magnitude.
[0056] While any adequate energy storage devices may be
used for storing the electrical energy generated by the
generator, it should be understood that the characteristics
of the storage device will affect the end performance of the
lock system. In one embodiment, a critical factor for the
selection of the energy storage device may be the self-
discharge characteristics. The internal leakage limits the
time interval between uses of the lock system. However, by
adequately choosing low leakage components, a time interval
between uses of several months or even a full year may be
obtained. Another important factor may be the ability for the
energy storage device to accumulate the energy generated by
the generator during a short period of time, i.e. the period
of time during which the door lever is operated.
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[0057] In one embodiment where the lock has not been used
for a period of time long enough for depleting the storage
device so that the level of charge would not be sufficient
for an opening cycle, the lever would need to be operated in
order to recharge the capacitor prior to entering the user
ID.
[0058] The remaining resistors, capacitors, diodes and
other circuit elements not otherwise described in detail
above with reference to Figure 4 are employed as components
of time constant networks, current limiting elements,
protection or filtering networks which are fully understood
by the person skilled in the art, thereby not requiring
further detailed description.
[0059] The embodiments of the invention described above
are intended to be exemplary only. The scope of the invention
is therefore intended to be limited solely by the scope of
the appended claims.
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